1. Field of the Invention
The area of the present invention is that of loading barges and other floating vessels and, more particularly, the automatic loading of such vessels through the continuous measurement of the draft and inclination of the vessel.
2. Background Art
The present invention is directed towards the loading of barges and other floating vessels and the ability to automate the loading process. What is critical in the loading process is to insure that the load is uniform such that the barge lies level in the water at the completion of loading. In addition, it is required that the draft of the vessel be known so that the barge does not bottom out in the waterway (river, channel, bay or sea) in which it will be traveling. This information, if measured accurately, can also be used to determine the weight of the load by enabling the calculation of the water displaced.
As indicated, when a barge is fully loaded it is important that the barge lies level in the water. Out-of-level barges have increased hydrodynamic drag as they are being towed or pushed through the water. This increased drag results in increased fuel expenditures for the vessel which is towing or pushing the barge. Hence, accurate leveling of the barge during loading will result in significant fuel savings.
Currently, barges are loaded by having a human operator direct the delivery of the cargo to the barge via a conveyor, crane, etc. The type of device used to load the barge will depend on the type of material to be loaded (coal, iron ore, steel beams, etc.). Periodically during the loading process, an assistant must walk around the periphery of the barge and peer over the side at draft marks on the hull to estimate the draft of the barge. This procedure is dangerous, costly, and inaccurate. It is known that persons performing this task have fallen into the water and have been subject to injury due to impact with the dock, flotsam, the barge, etc.
Draft determination during loading is critical. Overloaded barges may bottom out during transit resulting in potential spills, lost time, increased cost if the barge has to be repaired or refloated, etc. Relying on human observations of worn and faded draft marks not only exposes these individuals to risk, it increases the loadout time, especially if no observation is made until after the barge has been overloaded. In such a case, the barge will have to be towed to a separate location where the cargo can be off loaded and then towed back to the loading point to be reloaded.
U.S. Pat. No. 4,215,965 issued to Parsons describes an automatic loading system for floating vessels. With this approach, the vessel is moved fore-and-aft via a dock winch during loading. The loading process itself is completed using a delivery chute connected to a conveyer. Flowable material is delivered via the conveyer and through the chute into the barge. The loading point is adjusted through the use of a load level sensor in the form of a tilt switch. The switch operates so as to provide a dockside controller with information regarding the height of the load. At the same time, a list sensor provides information regarding the barge's list in the fore-and-aft plane. Loading proceeds until a prescribed amount of material has been delivered into the barge, which is in a level condition upon completion.
Although the above-described loading method allows for automation of the process, no attempt is made to eliminate the need for human observation of the draft of the barge. As previously indicated, this observation process can be very hazardous. Knowing the draft of the barge is critical during the loading process because the depth of a given waterway will change with seasons, amounts of precipitation, tides, etc. In addition, the above apparatus relies on hard wired connections between the tilt sensor, the list sensor and a controller. As is familiar to persons working in dockside loading operations, a number of hazards to such hard wired connections exist from moving vehicles and the like.